1. Field of Invention
This invention relates to projectile propulsion methods and apparatuses, specifically to cartridge-free projectile propulsion.
2. Prior Art
Projectile propulsion using traditional cartridge-based rounds have inherent disadvantages including ammunition weight and volumetric inefficiencies, cartridge “policing” and spent brass, cartridge ejection issues, ammunition storage and logistics problems, ammunition transport issues, cartridge manufacture, overall cost, propellant availability, and other drawbacks. Solutions that can provide competitive alternatives have long been sought and are in significant demand. Projectile-based weapons, for instance, are one application where practical cartridge-free solutions would be a tremendous advantage. Prior to this invention, however, there were no viable solutions which enabled cartridge-free projectile propulsion methods to be competitive with cartridge rounds within the same domain.
Experiments have been conducted with devices such as rail guns and ram accelerators, but their practicality in most domains has not been theoretically nor experimentally demonstrated with any assuredness, at least not in the short and mid terms. On the other hand, injection combustion techniques (a term used to describe those systems whereby a propellant or propellants is injected into a combustion chamber, as in an automobile or rocket engine) could provide an effective means of projectile propulsion in general, including within the domain currently dominated by traditional cartridge techniques.
One can calculate that, due to the abundance of available energy inherent in the technique, the system is viable, provided enough power could be delivered to the projectile in a reasonably efficient manner. Until this invention, existing projectile propulsion devices using any variant of injection-combustion style techniques, inclusive of all such devices in even in the broadest sense (including high-end experimental light gas guns down to recreational devices such as “spudguns”) have not developed the physical nor theoretical mechanisms whereby such injection-combustion techniques could be used in a practicably competitive fashion with cartridge rounds within the current cartridge-based device domain. For instance, there exists a commercially available paintball launching device employing propane; this device does not possess the required mechanisms for automatic propellant injection, full/semi-automatic fire, or the required higher-power capacities for operating in the domain dominated by cartridge-based devices, among other deficiencies. Additionally, injection-combustion devices which exhibit selective-fire and/or variable-velocity projectiles have not been demonstrated in the scientific/research areas or recreational domains, areas which have been dominated by powder and/or compressed gas devices.
Projectile propulsion devices using injectable propellants have resulted in patents, but research has not indicated that any have resulted in a viable practical implementation of such a device, specifically regarding a system which could compete with cartridge-based solutions and/or provide variable velocity projectiles or full-automatic firing capabilities.
Previous considerations using injectable fuels for projectile propulsion have been regarded as a reasonable choice since at least 1890, when Hiram S. Maxim received U.S. Pat. No. 424,119, “Gun”, for a device using fuel-air mixtures to propel grenades; this device was directed in scope towards single-shot, low-pressure grenade-type projectiles. Patents including U.S. Pat. No. 2,088,503 (“Cannon”), U.S. Pat. No. 2,965,000 (“Liquid Propellant, Regenerative Feed and Recoiless Gun”), U.S. Pat. No. 3,160,064 (“Liquid Propellant Gun”), U.S. Pat. No. 3,888,159 (“Liquid Propellant Weapon”), U.S. Pat. No. 4,005,632 (“Liquid Propellant Gun”), U.S. Pat. No. 4,993,309 (“Liquid Propellant Weapon System”), and U.S. Pat. No. 5,591,932 (“Break Action Cannon”), all refer to the use of liquid fuels for powering weapon projectiles. Most refer to large caliber weapons, either bulk-loaded or regenerative liquid propellant guns (RLPGs); these systems have difficulties in propellant feed, combustion stability, and machine complexity; plus, there is no indication of how such could be adopted for a small arms domain, or employ variable velocity projectiles, or in most cases be adapted for full-automatic or selective-fire capabilities; none appear adaptable or flexible enough for general purpose application. Moreover, practical implementation of a viable platform has not yet been shown as feasible.
Novel mechanisms are therefore required to advance injection-combustion techniques in order to develop viable alternatives for projectile propulsion applications. Such advancements include items such as propellant injection and metering systems, valve mechanisms, specific cycling operational methods, and other items. In addition to providing an alternative to cartridge-based systems, general projectile propulsion applications (ranging from scientific/research to recreation) would also benefit from the improvements in such techniques.